NEW YORK – Merck announced on Tuesday that the US Food and Drug Administration has accepted its supplemental biologics license application for the accelerated approval of pembrolizumab (Keytruda) as a monotherapy for previously treated cancer patients who have a high tumor mutational burden.
The agency also granted priority review for the sBLA, and Merck expects to hear back from the agency by mid-June. In a statement Merck said it is seeking approval for pembrolizumab as a treatment for adult and pediatric patients with unresectable or metastatic solid tumors, who have high TMB, who have progressed on other therapies, and who have no alternative treatment options.
If the application is successful, this will be the second pan-cancer indication for pembrolizumab. The FDA in 2017 approved the drug for advanced solid tumor patients who were out of options and whose tumors had microsatellite instability and mismatch repair deficiency.
The latest sBLA is supported by results from the Phase II KEYNOTE-158 trial, which also provided data supporting the first pan-cancer approval of the drug in MSI-H and dMMR solid cancers. At the European Society for Medical Oncology's annual meeting last year, researchers presented data from this study stratifying patients based on TMB status and showed that more patients with high TMB saw their tumors shrink while receiving pembrolizumab compared to those with low TMB.
In the trial, patients' tissue tumor mutational burden status was determined using Foundation Medicine's FoundationOne CDx assay. High mutational burden in this sBLA is defined as greater than or equal to 10 mutations/megabase.